PDE4D and Alzheimer disease: While PDE4 inhibitors such as apremilast have gained FDA approval for psoriasis, and while ongoing trials are evaluating their use in AD, the adverse effects, such as gastrointestinal toxicity, associated with these inhibitors remain a significant limitation hindering their clinical use.[48, 49] Our results suggest that cinobufagin, with its dual ability to inhibit PDE4D and suppress MIF‐mediated inflammation, as a promising therapeutic candidate.